textproduct: Quad Cities

KEY MESSAGES

- There is a Marginal (level 1 out of 5) Risk for severe storms Thursday and Friday for the entire area. Damaging winds and heavy rain are the primary risks.

- There is a Slight (level 2 out of 4) Risk for excessive rainfall Thursday and Friday. If storms repeat over the same areas, flash flooding is possible.

- The active weather pattern will bring a daily risk of showers and thunderstorms through the weekend. HOWEVER, there will be many hours of dry weather each day.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 209 PM CDT Wed Aug 12 2026

The morning MCS partially worked over the atmosphere. Since the atmosphere was not completely worked over, isolated to scattered (15- 40%) showers and some thunderstorms will be possible into early evening.

A break in the rain is possible during the evening. However, a weak LLJ develops after midnight with yet another thunderstorm complex, possibly in the form of an MCS, developing that moves into eastern Iowa in the pre-dawn hours. A localized severe storm is possible. Heavy rainfall is a given with the high moisture levels in the atmosphere.

The weak frontal boundary will vacillate across the area Thursday into Thursday night. Where the boundary is located will dictate where the organized storm clusters will develop/track. Outflow boundaries from the storm clusters will then provide additional foci for diurnal development on Thursday or allowing low end convection to persist.

Although the overall severe risk is low, the CAPE built up in the atmosphere will allow some severe storms to develop. The primary risk with any severe storm will be damaging winds and heavy rainfall. Hail is a secondary risk.

Although the overall rain chances are quite high, there will be hours of dry weather Thursday and Thursday night.

Given the potential for cloud cover and persistent showers/storms no heat advisory for Thursday will be issued at this time. If a heat advisory is needed for Thursday, it will be a tactical issuance based on trends in shower/storm coverage and evolution.

One area that is a concern is the continued heavy rainfall. If storms repeat over areas where the ground is quite moist, then flooding would be possible. Area waterways will see rises occur but there is no clear signal if any flooding would occur.

LONG TERM /FRIDAY THROUGH WEDNESDAY/

Issued at 250 AM CDT Wed Aug 12 2026

Friday through Tuesday...Latest ensemble and upper jet trends suggest the upper ridge and heat dome to get presses eastward again with some amplitude thrust up the mid to upper MS RVR Valley with west coast L/W troffiness establishment. This could make for another heat and storm track battle zone on Friday for the region, until the track then gets shunted more to the north acrs MN and WI while we heat up again. Still on the southern fringe, couldn't rule out MCS seepage down this far south into the local at times over the weekend as well. The action may last into early next week with longer range signs of upper ridge dampening and flattening to get us back under the influence of ring of fire periphery.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 716 PM CDT Wed Aug 12 2026

After brief periods of BKN MVFR cloud ceilings this evening, VFR conditions should prevail through most of the night. Closer to sunrise, patchy fog could develop near DBQ, MLI, and BRL with MVFR visibilities (40-70% chance) for 1-3 hours. Another round of showers and storms is likely tomorrow morning and early afternoon (14 UTC to 19 UTC) with a medium chance (40-60%) of lightning being observed during the period. With the heavier storms, ceilings and visibility could drop below IFR conditions briefly. The bulk of the precipitation should exit all TAF sites by the early afternoon with general VFR conditions returning. Isolated showers and storms could develop in the mid-to-late afternoon. PROB30s for these storms were utilized, but most sites should stay dry. In terms of wind gusts, there is a 20-40% chance of gusts exceeding 30 knots, but this percentage could increase depending on the organization of the storms in the morning.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.